Protein Calculator for Muscle Gain — Where It Plateaus

For muscle gain the useful question is not how high protein can go, but where it stops paying. A meta-analysis of 49 resistance-training trials found gains flattening at about 1.6 g per kilogram of body weight per day. The calculator below runs at 2.0 g/kg, comfortably above that line.

The plateau, with its uncertainty attached

Morton and colleagues pooled 49 randomized trials covering 1,863 participants and reported that “protein supplementation beyond total protein intakes of 1.62 g/kg/day resulted in no further RET-induced gains in FFM” — resistance exercise training, fat-free mass.

The number that usually gets dropped is the confidence interval around that breakpoint: 1.03 to 2.20 g/kg/day. That width is the honest picture. The best estimate of the plateau is 1.6, and the data cannot rule out a personal plateau near 2.2, which is exactly why the practical advice lands where it does:

• International Society of Sports Nutrition (2017): 1.4 to 2.0 g/kg/day “is sufficient for most exercising individuals.”
• Dietitians of Canada, the Academy of Nutrition and Dietetics and ACSM (2016): 1.2 to 2.0 g/kg/day, with the upper end for intensified training or reduced calories.

Anything above roughly 2.2 g/kg is not supported by the trials as producing more muscle. It is not dangerous for a healthy adult — see too much protein side effects — it simply does nothing extra.

How much of this is actually “extra”?

Less than it used to be, and this page would be misleading if it kept implying otherwise. The Dietary Guidelines for Americans, 2025–2030 set a goal of 1.2 to 1.6 g/kg per day for the general population. Lay the ranges over each other:

Range	Source	Relative to the federal goal
1.2–1.6 g/kg	Dietary Guidelines 2025–2030	the goal itself
1.2–2.0 g/kg	DC / Academy / ACSM, athletes	starts at the goal, extends past it
1.4–2.0 g/kg	ISSN, exercising individuals	overlaps the top half, extends past it
~1.6 g/kg	Morton meta-analysis plateau	the ceiling of the federal goal

The plateau for muscle gain lands exactly on the top of the general recommendation. So the honest version is: training does not put you in a different nutritional category. It puts you at the top of the range everyone is already aimed at, and gives you a reason to go slightly beyond it — to 1.8 or 2.0 g/kg — rather than a mandate.

That also means the gap between “eating for health” and “eating for hypertrophy” is now roughly 0.4 g/kg. For a 180 lb lifter that is about 33 g a day, or one extra serving.

Your number in pounds

Divide by 2.205 first, then multiply:

Body weight	In kilograms	1.6 g/kg	2.0 g/kg	2.2 g/kg
130 lb	59.0 kg	94 g	118 g	130 g
150 lb	68.0 kg	109 g	136 g	150 g
180 lb	81.6 kg	131 g	163 g	180 g
200 lb	90.7 kg	145 g	181 g	200 g
230 lb	104.3 kg	167 g	209 g	229 g

There is a coincidence in the last column worth noticing: 2.2 g/kg is almost exactly one gram per pound, since a pound is 0.4536 kg and 2.2 × 0.4536 = 1.0. The gym rule of “a gram per pound” is not folklore after all — it is the top of the published range, restated in American units. It is the ceiling, not the target.

Dose per meal, not just per day

Both position papers moved the emphasis from the daily total to how it is spread. The joint DC/Academy/ACSM paper: muscle adaptation “can be maximized by ingesting these targets as 0.3 g/kg BW after key exercise sessions and every 3 to 5 hours over multiple meals.” The ISSN version: 0.25 g/kg of a high-quality protein, or an absolute dose of 20 to 40 g.

For a 180 lb lifter that is roughly 25 g per feeding, four to five times a day. Doses above about 40 g have not been shown to push muscle protein synthesis further in most people.

Protein is one input of three

Protein is the material. It does not substitute for the other two:

1. Progressive resistance training — the signal. Without it, extra protein is just calories.
2. Enough total energy. The joint position paper is explicit that adequate energy intake matters so that amino acids are spared for protein synthesis instead of being burned as fuel.
3. Protein at the target, spread across the day.

Missing any one of them stalls the result. And if you are trying to gain muscle while losing fat, the target shifts toward the weight loss protein calculator — the range overlaps, the reasoning does not. BMI is a poor progress metric here for the obvious reason, which BMI for athletes covers.

This content is informational and does not replace evaluation by a physician or a registered dietitian.